You've correctly identified the issues and come up with a good solution for what you think would make it fun. Excellent job and I think you figured it out properly.
As I state on my post though,
I like that idea and think it would be fun. The issue is your idea has a different objective than the one they're releasing. They are targeting whales and large bot farmers/services with their approach in an attempt to create a lot of demand for assets. Your idea would be a good mode for the average person to play, and that's a future objective - just not this one.
RE: Splinterlands | How To Fix Survival Mode!